Seamless ball structure

ABSTRACT

A seamless ball structure, particularly suitable for balls used in different ball games, such as soccer, volleyball and basketball, includes an inner bladder, and an inner yarn layer, an emulsion layer and an outer cover layer sequentially provided on an outer surface of the inner bladder from inner to outer side. The emulsion layer inwardly permeates into voids among the yarns of the inner yarn layer. The outer cover layer is attached at an inner fabric layer thereof to an outer surface of the emulsion layer. The emulsion layer being heated and pressurized is in an adhering state to sufficiently tightly attach to the inner yarn layer and the outer cover layer, giving the ball so formed an increased structural strength. The ball can be easily and quickly manufactured at reduced manufacturing cost to thereby provide an improved ball structure that does not require any sewing with threads.

FIELD OF THE INVENTION

The present invention relates to a seamless ball structure, and more particularly to a seamless ball structure advantageously suitable for balls of different ball games, such as soccer, volleyball and basketball.

BACKGROUND OF THE INVENTION

Conventionally, most of the balls for use in sports games or recreational activities, such as soccer and volleyball, have a structure including a rubber-made inner bladder forming a center of the ball and wrapped around by an outer cover formed of a canvas fabric.

Please refer to FIG. 1 that shows a first conventional ball structure, which includes an inner bladder 10, an inner sewed layer 11, and an outer sewed layer 12. To manufacture the first conventional ball structure, first cut the canvas fabric into a plurality of identical and specifically shaped pieces. Then, apply an adhesive 13 on an inner surface of the pieces of the sew-up outer layer 12 for the same to attach to the pieces of the inner sewed layer 11. Further, the adhesive 13 is dried with heat, and the adhered pieces of inner and outer sewed layers are sewed together to form a bag-shaped body, which is then turned inside out for receiving the inner bladder 10 therein before being sealed and inflated into a desired shape.

In the above-described conventional ball structure, the joints of any two adjacent pieces, that is, the seams 14 on the ball are subject to deformation when being pulled, bringing sewing threads thereat to gradually expose to external environment and even become broken when the ball has been used over a long time. The inner and outer sewed layers 11, 12 are usually made of canvas, which prevents the inner and outer sewed layers 11, 12 from being easily firmly attached to one another in the adhering process. Further, as a result of shearing action, the inner and the outer sewed layer 11, 12 tend to dislocate from each other and become skewed.

FIG. 2 shows a second conventional ball structure, which includes an inner bladder 20, an inner yarn layer 21, and an outer sewed layer 22. A filling material 24 is first provided to an inner side the outer sewed layer 22, and then, an adhesive 23 is applied on an inner surface of the filling material 24 to thereby attach the outer sewed layer 22 to the inner yarn layer 21. In the second conventional ball structure, the inner yarn layer 21 is used to replace the inner sewed layer 11 in the first conventional ball structure, and the filling material 24 is provided to increase an overall thickness and accordingly, a structural strength of the ball to avoid possible deformation and breaking thereof. While the second ball structure is structurally strengthened, the sewed outer layer 22 thereof is still subject to the same problem as in the first conventional ball structure shown in FIG. 1. Further, since the second conventional ball structure has joints or seams 25 that have a reduced thickness compared to the seams 14 in the first conventional ball structure, the seams 25 are more easily deformed and broken under a shearing force.

FIG. 3 shows a third conventional ball structure, which includes an inner bladder 30, an inner sewed layer 31, an outer sewed layer 32 adhered to the inner sewed layer 31 using an adhesive 33, and an outer cover layer 35. The outer cover layer 35 is adhered to an outer surface of the outer sewed layer 32 in a staggered relation, so that seams 34 on the outer sewed layer 32 are not exposed to the external environment. While the outer cover layer 35 increases the overall thickness and the structural strength of the third conventional ball structure, the inner sewed layer 31 and the outer sewed layer 32 are still subject to the same problem as the first conventional ball structure shown in FIG. 1. That is, the seams 34 tend to deform or break and therefore form bumps on the surface of the ball, making the ball not suitable for use.

As can be seen from the above description, in addition to their respective disadvantages, all the three conventional ball structures have the problems caused by the sewed inner and outer layers, such as deformed and broken sewing threads due to shearing stress applied thereto. It is therefore desirable to improve such problems.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide a seamless ball structure that has increased structural strength and overcomes the problem of deformed and broken sewing threads as found in the conventional ball structures.

Another object of the present invention is to provide a seamless ball structure that can be easily and quickly manufactured at reduced manufacturing cost.

To achieve the above and other objects, the seamless ball structure according to the present invention includes an inner bladder forming a center of the ball structure; an inner yarn layer being wound around an outer surface of the inner bladder; an emulsion layer being applied to an outer surface of the inner yarn layer; and an outer cover layer being attached to an outer surface of the emulsion layer.

In an operable embodiment of the present invention, the outer cover layer is further applied on an inner surface thereof with another emulsion layer.

In another operable embodiment of the present invention, the ball is heated and pressurized after the outer cover layer is attached to the emulsion layer, so that the emulsion layer is in an adhering state.

In a preferred embodiment of the present invention, the outer cover layer includes at least an inner fabric layer for inwardly directly attaching to the emulsion layer; a seamless outer layer being formed of a plurality of identically shaped pieces, which are orderly placed adjacent to one another to complete the seamless outer layer; and a filling material being sandwiched between the inner fabric layer and the seamless outer layer.

In a preferred embodiment of the present invention, the seamless outer layer is made of a thermoplastic polyurethane material (TPU), and the filling material is ethylene vinyl acetate (EVA).

The ball according to the present invention is formed of an inner yarn layer, an outer cover layer and an intermediate emulsion layer without the need of sewing adjacent segments together using threads as in the prior art ball structures. Therefore, the ball according to the present invention is not disadvantageously subject to exposed or broken sewing threads under an externally applied force, and has increased structural strength. Moreover, the ball according to the present invention can be more easily and efficiently manufactured at reduced manufacturing cost to thereby provide an improved ball structure that does not require any sewing and is seamless.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein

FIG. 1 is a fragmentary sectional view of a first conventional ball structure;

FIG. 2 is a fragmentary sectional view of a second conventional ball structure;

FIG. 3 is a fragmentary sectional view of a third conventional ball structure;

FIG. 4 is a cutaway view of a seamless ball structure according to a preferred embodiment of the present invention;

FIG. 5 is a fragmentary sectional view of the seamless ball structure according to FIG. 4; and

FIG. 6 is a pictorial flow chart illustrating the steps of manufacturing the seamless ball structure according to an operable embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A preferred embodiment of the present invention is now described with more details with reference to the accompany drawing.

Please refer to FIGS. 4 and 5. A ball 40 with the seamless ball structure according to a preferred embodiment of the present invention includes an inflatable inner bladder 41, which is internally located at a center of the ball 40 and usually made of an elastic rubber material.

On an outer surface of the inner bladder 41, an inner yarn layer 42 having a predetermined thickness and fully attached to the inner bladder 41 is formed by winding a plurality of yarns around the inner bladder 41. With the inner yarn layer 42 being formed of yarns, it is possible for the inner bladder 41 wound around by the inner yarn layer 42 to responsively expand and contract when the inner bladder 41 is inflated and deflated, respectively, without becoming wrinkled or deformed to produce an unsmooth surface of the inner bladder 41.

An emulsion prepared with a predetermined material is applied to an outer surface of the inner yarn layer 42 to form an emulsion layer 44 thereon. With the inner yarn layer 42 being formed of yarns, the emulsion layer 44 applied to the inner yarn layer 42 automatically uniformly permeates into the inner yarn layer 42 via voids among the yarns, so that the emulsion and the yarns have increased contact area between them.

Please refer to FIG. 6. According to the illustrated manufacturing flowchart, the inner bladder 41 with the emulsion layer 44 applied on the inner yarn layer 42 is immediately positioned in a heating and pressurizing apparatus 50. The heating and pressurizing apparatus 50 includes mutually closable upper and lower halves to internally define an inner space corresponding to the size and shape of the ball 40. Before positioning the half-finished product of the ball 40 in the heating and pressurizing apparatus 50, first orderly place a plurality of segments of an outer cover layer 43 on a surface of the inner space. Then, when the outer cover layer 43 is attached to the emulsion layer 44 of the half-finished product of the ball 40 positioned in the inner space, the heating and pressuring apparatus 50 is quickly heated and pressurized. In the process of heating and pressurizing, the emulsion layer 44 is in an adhesive state to thereby completely tightly adhere the inner yarn layer 42 to the outer cover layer 43. Meanwhile, the ball 40 is inflated via one side of the heating and pressurizing apparatus 50 while the latter is heated and pressurized, so that the ball 40 is expanded to a desired shape.

As can be seen from FIGS. 4 and 5, the outer cover layer 43 includes, from outer to inner side, at least one seamless outer layer 431, one filling material 432, and one inner fabric layer 433. The seamless outer layer 431 is a component directly visible by a user, and is integrated from a plurality of shaped pieces or segments that are placed adjacent to one another in the inner space of the heating and pressurizing apparatus 50. When the segments are differently shaped, they can together present different configurations, such as the configuration of a soccer ball, a volleyball, or a basketball. In a preferred manner of manufacturing, the seamless outer layer 431 can be made of a thermoplastic polyurethane material (TPU). The filling material 432 is used mainly to increase an overall thickness of the outer cover layer 43 and to further increase the structural strength of the ball 40, preventing the ball 40 against deformation and damage. In a preferred manufacturing manner, the filling material 432 can include, for example, ethylene vinyl acetate (EVA). The inner fabric layer 433 is an innermost layer of the outer cover layer 43 for inwardly adhering to the emulsion layer 44. Generally, the inner fabric layer 433 is formed of a fabric material with relatively coarse surface and high friction coefficient to ensure increased contact area between the inner fabric layer 433 and the emulsion layer 44 and prevent the outer cover layer 43 against easy separation from the emulsion layer 44.

In another operable embodiment of the present invention, another layer of emulsion is first applied on the inner surface of the outer cover layer 43 before the half-finished product of the ball 40 is positioned in the heating and pressurizing apparatus 50, so that both the inner yarn layer 42 on the inner bladder 41 and the inner fabric layer 433 on the outer cover layer 43 are fully permeated by the emulsion before they are placed in the heating and pressurizing apparatus 50. Then, when being heated and pressurized, the emulsion in both of the inner yarn layer 42 and the inner fabric layer 433 is molten to firmly bind the two components to each other, giving the ball 40 an increased structural strength.

The ball 40 according to the present invention is formed of an inner yarn layer, an outer cover layer and an intermediate emulsion layer without the need of sewing adjacent segments together using threads as in the prior art ball structures. Therefore, the ball 40 according to the present invention is not disadvantageously subject to exposed or broken sewing threads under an externally applied force, and has increased structural strength. Moreover, the ball 40 according to the present invention can be more easily and efficiently manufactured at reduced manufacturing cost. Thus, the ball 40 is an improved ball structure that does not require any sewing and is therefore seamless.

The present invention has been described with a preferred embodiment thereof and it is understood that many changes and modifications in the described embodiment can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims. 

1. A seamless ball structure, comprising: an inner bladder forming a center of the ball structure; an inner yarn layer being wound around an outer surface of the inner bladder; an emulsion layer being applied to an outer surface of the inner yarn layer; and an outer cover layer being attached to an outer surface of the emulsion layer.
 2. The seamless ball structure as claimed in claim 1, wherein the outer cover layer is further applied on an inner surface thereof with another emulsion layer.
 3. The seamless ball structure as claimed in claim 1, wherein the ball structure is heated and pressurized after the outer cover layer is attached to the outer surface of the emulsion layer, so that the emulsion is in an adhering state.
 4. The seamless ball structure as claimed in claim 1, wherein the outer cover layer includes at least: an inner fabric layer for inwardly directly attaching to the emulsion layer; a seamless outer layer being formed of a plurality of identically shaped pieces, which are orderly placed adjacent to one another to complete the seamless outer layer; and a filling material being sandwiched between the inner fabric layer and the seamless outer layer.
 5. The seamless ball structure as claimed in claim 4, wherein the seamless outer layer is made of a thermoplastic polyurethane material (TPU), and the filling material is ethylene vinyl acetate (EVA). 